Update BUGS, README and TODO files

Signed-off-by: Niklas Koep <niklas.koep@gmail.com>
Eat mouse events for event.button > 3 of TreeViews

Signed-off-by: Niklas Koep <niklas.koep@gmail.com>
Don't emit BlaFetcher signals in the main thread

Instead of pushing all signal emissions to the main thread via
gobject.idle_add calls we now decorate the respective signal callbacks
with blautil.idle instead.

Signed-off-by: Niklas Koep <niklas.koep@gmail.com>
Add additional DND operations to playlists

Signed-off-by: Niklas Koep <niklas.koep@gmail.com>
Fix bug which causes setup.py build_ext to fail

Signed-off-by: Niklas Koep <niklas.koep@gmail.com>